The invention discloses a safe and precise 
cutting method for lower 
metal arranged wire. The safe and precise 
cutting method comprises the following steps: step one, using a 
focused ion beam technology according to the following procedures to realize 
cutting of the lower 
metal wires: during 
etching, enabling an IEE (Insulator Enhanced 
Etching) needle to enter a 
reaction chamber without opening a valve of the needle, 
etching under the conditions that the 
residence time of an iron beam on each pixel is 1 
microsecond and the area overlapping proportion is 50%, wherein the size of the outermost 
etching frame is more than 10mm * 10mm, the size of a new etching frame every time is needed to be at least 10% less than that of the previous frame, the new etching frame does not include 
metal wires exposed by the previous etching frame, the etching end point is the next layer of exposed metal wires at the position with an interval of more than 1mm with the exposed metal wires so as to 
expose the metal wires to be 
cut; step two, cutting the metal wires, etching for 20-50 seconds, and cutting the metal wires; step three, finally cleaning all etching frames through the enhanced etching mode by using a beam current between 500pA and 1000pA. With the adoption of the safe and precise cutting method, the line repair efficiency and success rate of chips are improved, thus, the debugging process during the initial stage of 
chip design is greatly quickened, the speed of 
failure analysis is increased, the speed of entering the market of the product is increased, and the 
mass production yield of chips is increased.